1
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Blaize JL, Garzon JLN, Howlett NG. FANCD2 genome binding is nonrandom and is enriched at large transcriptionally active neural genes prone to copy number variation. Funct Integr Genomics 2024; 24:180. [PMID: 39365306 PMCID: PMC11452531 DOI: 10.1007/s10142-024-01453-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2024] [Revised: 09/01/2024] [Accepted: 09/10/2024] [Indexed: 10/05/2024]
Abstract
Fanconi anemia (FA) is a rare genetic disease characterized by congenital abnormalities and increased risk for bone marrow failure and cancer. Central nervous system defects, including acute and irreversible loss of neurological function and white matter lesions with calcifications, have become increasingly recognized among FA patients, and are collectively referred to as Fanconi Anemia Neurological Syndrome or FANS. The molecular etiology of FANS is poorly understood. In this study, we have used a functional integrative genomics approach to further define the function of the FANCD2 protein and FA pathway. Combined analysis of new and existing FANCD2 ChIP-seq datasets demonstrates that FANCD2 binds nonrandomly throughout the genome with binding enriched at transcription start sites and in broad regions spanning protein-coding gene bodies. FANCD2 demonstrates a strong preference for large neural genes involved in neuronal differentiation, synapse function, and cell adhesion, with many of these genes implicated in neurodevelopmental and neuropsychiatric disorders. Furthermore, FANCD2 binds to regions of the genome that replicate late, undergo mitotic DNA synthesis (MiDAS) under conditions of replication stress, and are hotspots for copy number variation. Our analysis describes an important targeted role for FANCD2 and the FA pathway in the maintenance of large neural gene stability.
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Affiliation(s)
- Justin L Blaize
- Department of Cell and Molecular Biology, University of Rhode Island, 379 Center for Biotechnology and Life Sciences, 120 Flagg Road, Kingston, RI, USA
| | - Jada Lauren N Garzon
- Department of Cell and Molecular Biology, University of Rhode Island, 379 Center for Biotechnology and Life Sciences, 120 Flagg Road, Kingston, RI, USA
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Niall G Howlett
- Department of Cell and Molecular Biology, University of Rhode Island, 379 Center for Biotechnology and Life Sciences, 120 Flagg Road, Kingston, RI, USA.
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2
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Lebedin M, de la Rosa K. Diversification of Antibodies: From V(D)J Recombination to Somatic Exon Shuffling. Annu Rev Cell Dev Biol 2024; 40:265-281. [PMID: 39356809 DOI: 10.1146/annurev-cellbio-112122-030835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2024]
Abstract
Antibodies that gain specificity by a large insert encoding for an extra domain were described for the first time in 2016. In malaria-exposed individuals, an exon deriving from the leukocyte-associated immunoglobulin-like 1 (LAIR1) gene integrated via a copy-and-paste insertion into the immunoglobulin heavy chain encoding region. A few years later, a second example was identified, namely a dual exon integration from the leukocyte immunoglobulin-like receptor B1 (LILRB1) gene that is located in close proximity to LAIR1. A dedicated high-throughput characterization of chimeric immunoglobulin heavy chain transcripts unraveled, that insertions from distant genomic regions (including mitochondrial DNA) can contribute to human antibody diversity. This review describes the modalities of insert-containing antibodies. The role of known DNA mobility aspects, such as genomic translocation, gene conversion, and DNA fragility, is discussed in the context of insert-antibody generation. Finally, the review covers why insert antibodies were omitted from the past repertoire analyses and how insert antibodies can contribute to protective immunity or an autoreactive response.
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Affiliation(s)
- Mikhail Lebedin
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany;
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Kathrin de la Rosa
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany;
- Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Berlin, Germany
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3
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Kim S, Park SH, Kang N, Ra JS, Myung K, Lee KY. Polyubiquitinated PCNA triggers SLX4-mediated break-induced replication in alternative lengthening of telomeres (ALT) cancer cells. Nucleic Acids Res 2024:gkae785. [PMID: 39291733 DOI: 10.1093/nar/gkae785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 08/23/2024] [Accepted: 08/29/2024] [Indexed: 09/19/2024] Open
Abstract
Replication stresses are the major source of break-induced replication (BIR). Here, we show that in alternative lengthening of telomeres (ALT) cells, replication stress-induced polyubiquitinated proliferating cell nuclear antigen (PCNA) (polyUb-PCNA) triggers BIR at telomeres and the common fragile site (CFS). Consistently, depleting RAD18, a PCNA ubiquitinating enzyme, reduces the occurrence of ALT-associated promyelocytic leukemia (PML) bodies (APBs) and mitotic DNA synthesis at telomeres and CFS, both of which are mediated by BIR. In contrast, inhibiting ubiquitin-specific protease 1 (USP1), an Ub-PCNA deubiquitinating enzyme, results in an increase in the above phenotypes in a RAD18- and UBE2N (the PCNA polyubiquitinating enzyme)-dependent manner. Furthermore, deficiency of ATAD5, which facilitates USP1 activity and unloads PCNAs, augments recombination-associated phenotypes. Mechanistically, telomeric polyUb-PCNA accumulates SLX4, a nuclease scaffold, at telomeres through its ubiquitin-binding domain and increases telomere damage. Consistently, APB increase induced by Ub-PCNA depends on SLX4 and structure-specific endonucleases. Taken together, our results identified the polyUb-PCNA-SLX4 axis as a trigger for directing BIR.
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Affiliation(s)
- Sangin Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea
- Department of Biological Sciences, College of Information-Bio Convergence Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Su Hyung Park
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea
- Department of Biomedical Engineering, College of Information-Bio Convergence Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Nalae Kang
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea
| | - Jae Sun Ra
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea
| | - Kyungjae Myung
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea
- Department of Biomedical Engineering, College of Information-Bio Convergence Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Kyoo-Young Lee
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Korea
- Department of Biochemistry, College of Medicine, Hallym University, Chuncheon 24252, Gangwon-do, Republic of Korea
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4
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Sagi T, Sadato D, Takayasu K, Sasanuma H, Kanoh Y, Masai H. RNA-DNA hybrids on protein coding genes are stabilized by loss of RNase H and are associated with DNA damages during S-phase in fission yeast. Genes Cells 2024. [PMID: 39252397 DOI: 10.1111/gtc.13157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2024] [Revised: 08/15/2024] [Accepted: 08/23/2024] [Indexed: 09/11/2024]
Abstract
RNA-DNA hybrid is a part of the R-loop which is an important non-standard nucleic acid structure. RNA-DNA hybrid/R-loop causes genomic instability by inducing DNA damages or inhibiting DNA replication. It also plays biologically important roles in regulation of transcription, replication, recombination and repair. Here, we have employed catalytically inactive human RNase H1 mutant (D145N) to visualize RNA-DNA hybrids and map their genomic locations in fission yeast cells. The RNA-DNA hybrids appear as multiple nuclear foci in rnh1∆rnh201∆ cells lacking cellular RNase H activity, but not in the wild-type. The majority of RNA-DNA hybrid loci are detected at the protein coding regions and tRNA. In rnh1∆rnh201∆ cells, cells with multiple Rad52 foci increase during S-phase and about 20% of the RNA-DNA hybrids overlap with Rad52 loci. During S-phase, more robust association of Rad52 with RNA-DNA hybrids was observed in the protein coding region than in M-phase. These results suggest that persistent RNA-DNA hybrids in the protein coding region in rnh1∆rnh201∆ cells generate DNA damages during S-phase, potentially through collision with DNA replication forks.
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Affiliation(s)
- Tomoko Sagi
- Genome Dynamics Project, Department of Basic Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Daichi Sadato
- Clinical Research and Trials Center, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Tokyo, Japan
| | - Kazuto Takayasu
- Genome Dynamics Project, Department of Basic Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
- Department of Biosciences, School of Science, Kitasato University, Sagamihara, Kanagawa, Japan
| | - Hiroyuki Sasanuma
- Genome Dynamics Project, Department of Basic Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Yutaka Kanoh
- Genome Dynamics Project, Department of Basic Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Hisao Masai
- Genome Dynamics Project, Department of Basic Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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5
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Choi SY. The roles of TonEBP in the DNA damage response: From DNA damage bypass to R-loop resolution. DNA Repair (Amst) 2024; 140:103697. [PMID: 38878563 DOI: 10.1016/j.dnarep.2024.103697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 05/17/2024] [Accepted: 05/20/2024] [Indexed: 07/13/2024]
Abstract
Tonicity-responsive enhancer binding protein (TonEBP) is a stress-responsive protein that plays a critical role in the regulation of gene expression and cellular adaptation to stressful environments. Recent studies uncovered the novel role of TonEBP in the DNA damage response, which significantly impacts genomic stability. This review provides a comprehensive overview of the novel role of TonEBP in DNA damage repair, including its involvement in the DNA damage bypass pathway and the recognition and resolution of DNA damage-induced R-loop structures.
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Affiliation(s)
- Soo Youn Choi
- Department of Biology, Jeju National University, Jeju, the Republic of Korea.
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6
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Kannan A, Gangadharan Leela S, Branzei D, Gangwani L. Role of senataxin in R-loop-mediated neurodegeneration. Brain Commun 2024; 6:fcae239. [PMID: 39070547 PMCID: PMC11277865 DOI: 10.1093/braincomms/fcae239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 06/14/2024] [Accepted: 07/13/2024] [Indexed: 07/30/2024] Open
Abstract
Senataxin is an RNA:DNA helicase that plays an important role in the resolution of RNA:DNA hybrids (R-loops) formed during transcription. R-loops are involved in the regulation of biological processes such as immunoglobulin class switching, gene expression and DNA repair. Excessive accumulation of R-loops results in DNA damage and loss of genomic integrity. Senataxin is critical for maintaining optimal levels of R-loops to prevent DNA damage and acts as a genome guardian. Within the nucleus, senataxin interacts with various RNA processing factors and DNA damage response and repair proteins. Senataxin interactors include survival motor neuron and zinc finger protein 1, with whom it co-localizes in sub-nuclear bodies. Despite its ubiquitous expression, mutations in senataxin specifically affect neurons and result in distinct neurodegenerative diseases such as amyotrophic lateral sclerosis type 4 and ataxia with oculomotor apraxia type 2, which are attributed to the gain-of-function and the loss-of-function mutations in senataxin, respectively. In addition, low levels of senataxin (loss-of-function) in spinal muscular atrophy result in the accumulation of R-loops causing DNA damage and motor neuron degeneration. Senataxin may play multiple functions in diverse cellular processes; however, its emerging role in R-loop resolution and maintenance of genomic integrity is gaining attention in the field of neurodegenerative diseases. In this review, we highlight the role of senataxin in R-loop resolution and its potential as a therapeutic target to treat neurodegenerative diseases.
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Affiliation(s)
| | - Shyni Gangadharan Leela
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
| | - Dana Branzei
- The AIRC Institute of Molecular Oncology Foundation, IFOM ETS, Milan 20139, Italy
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), Pavia 27100, Italy
| | - Laxman Gangwani
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA
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7
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Wulfridge P, Sarma K. Intertwining roles of R-loops and G-quadruplexes in DNA repair, transcription and genome organization. Nat Cell Biol 2024; 26:1025-1036. [PMID: 38914786 DOI: 10.1038/s41556-024-01437-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 05/10/2024] [Indexed: 06/26/2024]
Abstract
R-loops are three-stranded nucleic acid structures that are abundant and widespread across the genome and that have important physiological roles in many nuclear processes. Their accumulation is observed in cancers and neurodegenerative disorders. Recent studies have implicated a function for R-loops and G-quadruplex (G4) structures, which can form on the displaced single strand of R-loops, in three-dimensional genome organization in both physiological and pathological contexts. Here we discuss the interconnected functions of DNA:RNA hybrids and G4s within R-loops, their impact on DNA repair and gene regulatory networks, and their emerging roles in genome organization during development and disease.
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Affiliation(s)
- Phillip Wulfridge
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, PA, USA
- Penn Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Kavitha Sarma
- Gene Expression and Regulation Program, The Wistar Institute, Philadelphia, PA, USA.
- Penn Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA.
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8
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Di Nardo M, Musio A. Cohesin - bridging the gap among gene transcription, genome stability, and human diseases. FEBS Lett 2024. [PMID: 38852996 DOI: 10.1002/1873-3468.14949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 04/15/2024] [Accepted: 05/08/2024] [Indexed: 06/11/2024]
Abstract
The intricate landscape of cellular processes governing gene transcription, chromatin organization, and genome stability is a fascinating field of study. A key player in maintaining this delicate equilibrium is the cohesin complex, a molecular machine with multifaceted roles. This review presents an in-depth exploration of these intricate connections and their significant impact on various human diseases.
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Affiliation(s)
- Maddalena Di Nardo
- Institute for Biomedical Technologies (ITB), National Research Council (CNR), Pisa, Italy
| | - Antonio Musio
- Institute for Biomedical Technologies (ITB), National Research Council (CNR), Pisa, Italy
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9
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Rojas P, Wang J, Guglielmi G, Sadurnì MM, Pavlou L, Leung GHD, Rajagopal V, Spill F, Saponaro M. Genome-wide identification of replication fork stalling/pausing sites and the interplay between RNA Pol II transcription and DNA replication progression. Genome Biol 2024; 25:126. [PMID: 38773641 PMCID: PMC11106976 DOI: 10.1186/s13059-024-03278-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 05/14/2024] [Indexed: 05/24/2024] Open
Abstract
BACKGROUND DNA replication progression can be affected by the presence of physical barriers like the RNA polymerases, leading to replication stress and DNA damage. Nonetheless, we do not know how transcription influences overall DNA replication progression. RESULTS To characterize sites where DNA replication forks stall and pause, we establish a genome-wide approach to identify them. This approach uses multiple timepoints during S-phase to identify replication fork/stalling hotspots as replication progresses through the genome. These sites are typically associated with increased DNA damage, overlapped with fragile sites and with breakpoints of rearrangements identified in cancers but do not overlap with replication origins. Overlaying these sites with a genome-wide analysis of RNA polymerase II transcription, we find that replication fork stalling/pausing sites inside genes are directly related to transcription progression and activity. Indeed, we find that slowing down transcription elongation slows down directly replication progression through genes. This indicates that transcription and replication can coexist over the same regions. Importantly, rearrangements found in cancers overlapping transcription-replication collision sites are detected in non-transformed cells and increase following treatment with ATM and ATR inhibitors. At the same time, we find instances where transcription activity favors replication progression because it reduces histone density. CONCLUSIONS Altogether, our findings highlight how transcription and replication overlap during S-phase, with both positive and negative consequences for replication fork progression and genome stability by the coexistence of these two processes.
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Affiliation(s)
- Patricia Rojas
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Jianming Wang
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Giovanni Guglielmi
- School of Mathematics, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
- Department of Biomedical Engineering, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Martina Mustè Sadurnì
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Lucas Pavlou
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Geoffrey Ho Duen Leung
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Vijay Rajagopal
- Department of Biomedical Engineering, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Fabian Spill
- School of Mathematics, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - Marco Saponaro
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
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10
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Corazzi L, Ionasz VS, Andrejev S, Wang LC, Vouzas A, Giaisi M, Di Muzio G, Ding B, Marx AJM, Henkenjohann J, Allers MM, Gilbert DM, Wei PC. Linear interaction between replication and transcription shapes DNA break dynamics at recurrent DNA break Clusters. Nat Commun 2024; 15:3594. [PMID: 38678011 PMCID: PMC11055891 DOI: 10.1038/s41467-024-47934-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 04/12/2024] [Indexed: 04/29/2024] Open
Abstract
Recurrent DNA break clusters (RDCs) are replication-transcription collision hotspots; many are unique to neural progenitor cells. Through high-resolution replication sequencing and a capture-ligation assay in mouse neural progenitor cells experiencing replication stress, we unravel the replication features dictating RDC location and orientation. Most RDCs occur at the replication forks traversing timing transition regions (TTRs), where sparse replication origins connect unidirectional forks. Leftward-moving forks generate telomere-connected DNA double-strand breaks (DSBs), while rightward-moving forks lead to centromere-connected DSBs. Strand-specific mapping for DNA-bound RNA reveals co-transcriptional dual-strand DNA:RNA hybrids present at a higher density in RDC than in other actively transcribed long genes. In addition, mapping RNA polymerase activity uncovers that head-to-head interactions between replication and transcription machinery result in 60% DSB contribution to the head-on compared to 40% for co-directional. Taken together we reveal TTR as a fragile class and show how the linear interaction between transcription and replication impacts genome stability.
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Affiliation(s)
- Lorenzo Corazzi
- German Cancer Research Center, 69120, Heidelberg, Germany
- Faculty of Bioscience, Ruprecht-Karl-University of Heidelberg, 69120, Heidelberg, Germany
| | - Vivien S Ionasz
- German Cancer Research Center, 69120, Heidelberg, Germany
- Faculty of Bioscience, Ruprecht-Karl-University of Heidelberg, 69120, Heidelberg, Germany
| | | | - Li-Chin Wang
- German Cancer Research Center, 69120, Heidelberg, Germany
| | - Athanasios Vouzas
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
- San Diego Biomedical Research Institute, San Diego, CA, 92121, USA
| | - Marco Giaisi
- German Cancer Research Center, 69120, Heidelberg, Germany
| | - Giulia Di Muzio
- German Cancer Research Center, 69120, Heidelberg, Germany
- Faculty of Bioscience, Ruprecht-Karl-University of Heidelberg, 69120, Heidelberg, Germany
- Interdisciplinary Center for Neurosciences, Ruprecht-Karl-University of Heidelberg, 69120, Heidelberg, Germany
| | - Boyu Ding
- German Cancer Research Center, 69120, Heidelberg, Germany
- Faculty of Bioscience, Ruprecht-Karl-University of Heidelberg, 69120, Heidelberg, Germany
- Faculty of Medicine, Ruprecht-Karl-University of Heidelberg, 69120, Heidelberg, Germany
| | - Anna J M Marx
- German Cancer Research Center, 69120, Heidelberg, Germany
- Faculty of Bioscience, Ruprecht-Karl-University of Heidelberg, 69120, Heidelberg, Germany
- Interdisciplinary Center for Neurosciences, Ruprecht-Karl-University of Heidelberg, 69120, Heidelberg, Germany
| | - Jonas Henkenjohann
- German Cancer Research Center, 69120, Heidelberg, Germany
- Faculty of Bioscience, Ruprecht-Karl-University of Heidelberg, 69120, Heidelberg, Germany
- Interdisciplinary Center for Neurosciences, Ruprecht-Karl-University of Heidelberg, 69120, Heidelberg, Germany
| | - Michael M Allers
- German Cancer Research Center, 69120, Heidelberg, Germany
- Faculty of Medicine, Ruprecht-Karl-University of Heidelberg, 69120, Heidelberg, Germany
| | - David M Gilbert
- San Diego Biomedical Research Institute, San Diego, CA, 92121, USA
| | - Pei-Chi Wei
- German Cancer Research Center, 69120, Heidelberg, Germany.
- Faculty of Bioscience, Ruprecht-Karl-University of Heidelberg, 69120, Heidelberg, Germany.
- Interdisciplinary Center for Neurosciences, Ruprecht-Karl-University of Heidelberg, 69120, Heidelberg, Germany.
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11
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Soheili-Nezhad S, Ibáñez-Solé O, Izeta A, Hoeijmakers JHJ, Stoeger T. Time is ticking faster for long genes in aging. Trends Genet 2024; 40:299-312. [PMID: 38519330 PMCID: PMC11003850 DOI: 10.1016/j.tig.2024.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/30/2024] [Accepted: 01/30/2024] [Indexed: 03/24/2024]
Abstract
Recent studies of aging organisms have identified a systematic phenomenon, characterized by a negative correlation between gene length and their expression in various cell types, species, and diseases. We term this phenomenon gene-length-dependent transcription decline (GLTD) and suggest that it may represent a bottleneck in the transcription machinery and thereby significantly contribute to aging as an etiological factor. We review potential links between GLTD and key aging processes such as DNA damage and explore their potential in identifying disease modification targets. Notably, in Alzheimer's disease, GLTD spotlights extremely long synaptic genes at chromosomal fragile sites (CFSs) and their vulnerability to postmitotic DNA damage. We suggest that GLTD is an integral element of biological aging.
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Affiliation(s)
- Sourena Soheili-Nezhad
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands; Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Olga Ibáñez-Solé
- Stem Cells & Aging Group, Biogipuzkoa Health Research Institute, Donostia-San Sebastián, Spain; Institute for Genome Stability in Aging and Disease, Medical Faculty, University and University Hospital of Cologne, Joseph-Stelzmann-Strasse 26, 50931 Cologne, Germany; Cologne Excellence Cluster for Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Strasse 26, 50931 Cologne, Germany
| | - Ander Izeta
- Stem Cells & Aging Group, Biogipuzkoa Health Research Institute, Donostia-San Sebastián, Spain; Tecnun-University of Navarra, 20018 Donostia-San Sebastian, Spain.
| | - Jan H J Hoeijmakers
- Department of Molecular Genetics, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands; University of Cologne, Faculty of Medicine, Cluster of Excellence for Aging Research, Institute for Genome Stability in Ageing and Disease, Cologne, Germany; Princess Maxima Center for Pediatric Oncology, Oncode Institute, Utrecht, The Netherlands.
| | - Thomas Stoeger
- Feinberg School of Medicine, Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, IL, USA; Potocsnak Longevity Institute, Northwestern University, Chicago, IL, USA; Simpson Querrey Lung Institute for Translational Science, Chicago, IL, USA.
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12
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Valenzisi P, Marabitti V, Pichierri P, Franchitto A. WRNIP1 prevents transcription-associated genomic instability. eLife 2024; 12:RP89981. [PMID: 38488661 PMCID: PMC10942783 DOI: 10.7554/elife.89981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2024] Open
Abstract
R-loops are non-canonical DNA structures that form during transcription and play diverse roles in various physiological processes. Disruption of R-loop homeostasis can lead to genomic instability and replication impairment, contributing to several human diseases, including cancer. Although the molecular mechanisms that protect cells against such events are not fully understood, recent research has identified fork protection factors and DNA damage response proteins as regulators of R-loop dynamics. In this study, we identify the Werner helicase-interacting protein 1 (WRNIP1) as a novel factor that counteracts transcription-associated DNA damage upon replication perturbation. Loss of WRNIP1 leads to R-loop accumulation, resulting in collisions between the replisome and transcription machinery. We observe co-localization of WRNIP1 with transcription/replication complexes and R-loops after replication perturbation, suggesting its involvement in resolving transcription-replication conflicts. Moreover, WRNIP1-deficient cells show impaired replication restart from transcription-induced fork stalling. Notably, transcription inhibition and RNase H1 overexpression rescue all the defects caused by loss of WRNIP1. Importantly, our findings highlight the critical role of WRNIP1 ubiquitin-binding zinc finger (UBZ) domain in preventing pathological persistence of R-loops and limiting DNA damage, thereby safeguarding genome integrity.
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Affiliation(s)
- Pasquale Valenzisi
- Section of Mechanisms Biomarkers and Models, Department of Environment and Health, Istituto Superiore di SanitaRomeItaly
| | - Veronica Marabitti
- Section of Mechanisms Biomarkers and Models, Department of Environment and Health, Istituto Superiore di SanitaRomeItaly
| | - Pietro Pichierri
- Section of Mechanisms Biomarkers and Models, Department of Environment and Health, Istituto Superiore di SanitaRomeItaly
| | - Annapaola Franchitto
- Section of Mechanisms Biomarkers and Models, Department of Environment and Health, Istituto Superiore di SanitaRomeItaly
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13
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Hidmi O, Oster S, Monin J, Aqeilan RI. TOP1 and R-loops facilitate transcriptional DSBs at hypertranscribed cancer driver genes. iScience 2024; 27:109082. [PMID: 38375218 PMCID: PMC10875566 DOI: 10.1016/j.isci.2024.109082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/26/2023] [Accepted: 01/28/2024] [Indexed: 02/21/2024] Open
Abstract
DNA double-stranded breaks (DSBs) pose a significant threat to genomic integrity, and their generation during essential cellular processes like transcription remains poorly understood. In this study, we employ several techniques to map DSBs, R-loops, and topoisomerase 1 cleavage complex (TOP1cc) to comprehensively investigate the interplay between transcription, DSBs, topoisomerase 1 (TOP1), and R-loops. Our findings reveal the presence of DSBs at highly expressed genes enriched with TOP1 and R-loops. Remarkably, transcription-associated DSBs at these loci are significantly reduced upon depletion of R-loops and TOP1, uncovering the pivotal roles of TOP1 and R-loops in transcriptional DSB formation. By elucidating the intricate interplay between TOP1cc trapping, R-loops, and DSBs, our study provides insights into the mechanisms underlying transcription-associated genomic instability. Moreover, we establish a link between transcriptional DSBs and early molecular changes driving cancer development, highlighting the distinct etiology and molecular characteristics of driver mutations compared to passenger mutations.
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Affiliation(s)
- Osama Hidmi
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Department of Immunology and Cancer Research-IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Sara Oster
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Department of Immunology and Cancer Research-IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Jonathan Monin
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Department of Immunology and Cancer Research-IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Rami I. Aqeilan
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Department of Immunology and Cancer Research-IMRIC, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
- Cyprus Cancer Research Institute (CCRI), Nicosia, Cyprus
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14
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Yang KB, Rasouly A, Epshtein V, Martinez C, Nguyen T, Shamovsky I, Nudler E. Persistence of backtracking by human RNA polymerase II. Mol Cell 2024; 84:897-909.e4. [PMID: 38340716 DOI: 10.1016/j.molcel.2024.01.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 11/20/2023] [Accepted: 01/22/2024] [Indexed: 02/12/2024]
Abstract
RNA polymerase II (RNA Pol II) can backtrack during transcription elongation, exposing the 3' end of nascent RNA. Nascent RNA sequencing can approximate the location of backtracking events that are quickly resolved; however, the extent and genome-wide distribution of more persistent backtracking are unknown. Consequently, we developed a method to directly sequence the extruded, "backtracked" 3' RNA. Our data show that RNA Pol II slides backward more than 20 nt in human cells and can persist in this backtracked state. Persistent backtracking mainly occurs where RNA Pol II pauses near promoters and intron-exon junctions and is enriched in genes involved in translation, replication, and development, where gene expression is decreased if these events are unresolved. Histone genes are highly prone to persistent backtracking, and the resolution of such events is likely required for timely expression during cell division. These results demonstrate that persistent backtracking can potentially affect diverse gene expression programs.
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Affiliation(s)
- Kevin B Yang
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Aviram Rasouly
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA; Howard Hughes Medical Institute, NYU Langone Health, New York, NY 10016, USA
| | - Vitaly Epshtein
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Criseyda Martinez
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Thao Nguyen
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Ilya Shamovsky
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Evgeny Nudler
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA; Howard Hughes Medical Institute, NYU Langone Health, New York, NY 10016, USA.
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15
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Corazzi L, Ionasz V, Andrejev S, Wang LC, Vouzas A, Giaisi M, Di Muzio G, Ding B, Marx AJM, Henkenjohann J, Allers MM, Gilbert DM, Wei PC. Linear Interaction Between Replication and Transcription Shapes DNA Break Dynamics at Recurrent DNA Break Clusters. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.22.554340. [PMID: 37662334 PMCID: PMC10473677 DOI: 10.1101/2023.08.22.554340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Recurrent DNA break clusters (RDCs) are replication-transcription collision hotspots; many are unique to neural progenitor cells. Through high-resolution replication sequencing and a capture-ligation assay in mouse neural progenitor cells experiencing replication stress, we unraveled the replication features dictating RDC location and orientation. Most RDCs occur at the replication forks traversing timing transition regions (TTRs), where sparse replication origins connect unidirectional forks. Leftward-moving forks generate telomere-connected DNA double-strand breaks (DSBs), while rightward-moving forks lead to centromere-connected DSBs. Strand-specific mapping for DNA-bound RNA revealed co-transcriptional dual-strand DNA:RNA hybrids present at a higher density in RDC than in other actively transcribed long genes. In addition, mapping RNA polymerase activity revealed that head-to-head interactions between replication and transcription machinery resulted in 60% DSB contribution to the head-on compared to 40% for co-directional. Our findings revealed TTR as a novel fragile class and highlighted how the linear interaction between transcription and replication impacts genome stability.
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16
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Li Y, Zhang Y, Shah SB, Chang CY, Wang H, Wu X. MutSβ protects common fragile sites by facilitating homology-directed repair at DNA double-strand breaks with secondary structures. Nucleic Acids Res 2024; 52:1120-1135. [PMID: 38038265 PMCID: PMC10853791 DOI: 10.1093/nar/gkad1112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 10/14/2023] [Accepted: 11/07/2023] [Indexed: 12/02/2023] Open
Abstract
Common fragile sites (CFSs) are regions prone to chromosomal rearrangements, thereby contributing to tumorigenesis. Under replication stress (RS), CFSs often harbor under-replicated DNA regions at the onset of mitosis, triggering homology-directed repair known as mitotic DNA synthesis (MiDAS) to complete DNA replication. In this study, we identified an important role of DNA mismatch repair protein MutSβ (MSH2/MSH3) in facilitating MiDAS and maintaining CFS stability. Specifically, we demonstrated that MutSβ is required for the increased mitotic recombination induced by RS or FANCM loss at CFS-derived AT-rich and structure-prone sequences (CFS-ATs). We also found that MSH3 exhibits synthetic lethality with FANCM. Mechanistically, MutSβ is required for homologous recombination (HR) especially when DNA double-strand break (DSB) ends contain secondary structures. We also showed that upon RS, MutSβ is recruited to Flex1, a specific CFS-AT, in a PCNA-dependent but MUS81-independent manner. Furthermore, MutSβ interacts with RAD52 and promotes RAD52 recruitment to Flex1 following MUS81-dependent fork cleavage. RAD52, in turn, recruits XPF/ERCC1 to remove DNA secondary structures at DSB ends, enabling HR/break-induced replication (BIR) at CFS-ATs. We propose that the specific requirement of MutSβ in processing DNA secondary structures at CFS-ATs underlies its crucial role in promoting MiDAS and maintaining CFS integrity.
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Affiliation(s)
- Youhang Li
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Yunkun Zhang
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Sameer Bikram Shah
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Chia-Yu Chang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Hailong Wang
- Beijing Key Laboratory of DNA Damage Response and College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Xiaohua Wu
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
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17
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Fenstermaker TK, Petruk S, Mazo A. An emerging paradigm in epigenetic marking: coordination of transcription and replication. Transcription 2024; 15:22-37. [PMID: 38378467 DOI: 10.1080/21541264.2024.2316965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 02/06/2024] [Indexed: 02/22/2024] Open
Abstract
DNA replication and RNA transcription both utilize DNA as a template and therefore need to coordinate their activities. The predominant theory in the field is that in order for the replication fork to proceed, transcription machinery has to be evicted from DNA until replication is complete. If that does not occur, these machineries collide, and these collisions elicit various repair mechanisms which require displacement of one of the enzymes, often RNA polymerase, in order for replication to proceed. This model is also at the heart of the epigenetic bookmarking theory, which implies that displacement of RNA polymerase during replication requires gradual re-building of chromatin structure, which guides recruitment of transcriptional proteins and resumption of transcription. We discuss these theories but also bring to light newer data that suggest that these two processes may not be as detrimental to one another as previously thought. This includes findings suggesting that these processes can occur without fork collapse and that RNA polymerase may only be transiently displaced during DNA replication. We discuss potential mechanisms by which RNA polymerase may be retained at the replication fork and quickly rebind to DNA post-replication. These discoveries are important, not only as new evidence as to how these two processes are able to occur harmoniously but also because they have implications on how transcriptional programs are maintained through DNA replication. To this end, we also discuss the coordination of replication and transcription in light of revising the current epigenetic bookmarking theory of how the active gene status can be transmitted through S phase.
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Affiliation(s)
- Tyler K Fenstermaker
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Svetlana Petruk
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Alexander Mazo
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
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18
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Hourvitz N, Awad A, Tzfati Y. The many faces of the helicase RTEL1 at telomeres and beyond. Trends Cell Biol 2024; 34:109-121. [PMID: 37532653 DOI: 10.1016/j.tcb.2023.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 07/01/2023] [Accepted: 07/05/2023] [Indexed: 08/04/2023]
Abstract
Regulator of telomere elongation 1 (RTEL1) is known as a DNA helicase that is important for telomeres and genome integrity. However, the diverse phenotypes of RTEL1 dysfunction, the wide spectrum of symptoms caused by germline RTEL1 mutations, and the association of RTEL1 mutations with cancers suggest that RTEL1 is a complex machine that interacts with DNA, RNA, and proteins, and functions in diverse cellular pathways. We summarize the proposed functions of RTEL1 and discuss their implications for telomere maintenance. Studying RTEL1 is crucial for understanding the complex interplay between telomere maintenance and other nuclear pathways, and how compromising these pathways causes telomere biology diseases, various aging-associated pathologies, and cancer.
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Affiliation(s)
- Noa Hourvitz
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Safra Campus, Jerusalem 91904, Israel
| | - Aya Awad
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Safra Campus, Jerusalem 91904, Israel
| | - Yehuda Tzfati
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Safra Campus, Jerusalem 91904, Israel.
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19
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Bournaka S, Badra-Fajardo N, Arbi M, Taraviras S, Lygerou Z. The cell cycle revisited: DNA replication past S phase preserves genome integrity. Semin Cancer Biol 2024; 99:45-55. [PMID: 38346544 DOI: 10.1016/j.semcancer.2024.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/23/2024] [Accepted: 02/05/2024] [Indexed: 02/20/2024]
Abstract
Accurate and complete DNA duplication is critical for maintaining genome integrity. Multiple mechanisms regulate when and where DNA replication takes place, to ensure that the entire genome is duplicated once and only once per cell cycle. Although the bulk of the genome is copied during the S phase of the cell cycle, increasing evidence suggests that parts of the genome are replicated in G2 or mitosis, in a last attempt to secure that daughter cells inherit an accurate copy of parental DNA. Remaining unreplicated gaps may be passed down to progeny and replicated in the next G1 or S phase. These findings challenge the long-established view that genome duplication occurs strictly during the S phase, bridging DNA replication to DNA repair and providing novel therapeutic strategies for cancer treatment.
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Affiliation(s)
- Spyridoula Bournaka
- Department of General Biology, Medical School, University of Patras, Patras 26504, Greece
| | - Nibal Badra-Fajardo
- Department of General Biology, Medical School, University of Patras, Patras 26504, Greece
| | - Marina Arbi
- Department of General Biology, Medical School, University of Patras, Patras 26504, Greece
| | - Stavros Taraviras
- Department of Physiology, Medical School, University of Patras, Patras 26504, Greece
| | - Zoi Lygerou
- Department of General Biology, Medical School, University of Patras, Patras 26504, Greece.
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20
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Viera T, Abfalterer Q, Neal A, Trujillo R, Patidar PL. Molecular Basis of XRN2-Deficient Cancer Cell Sensitivity to Poly(ADP-ribose) Polymerase Inhibition. Cancers (Basel) 2024; 16:595. [PMID: 38339346 PMCID: PMC10854503 DOI: 10.3390/cancers16030595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/19/2024] [Accepted: 01/22/2024] [Indexed: 02/12/2024] Open
Abstract
R-loops (RNA-DNA hybrids with displaced single-stranded DNA) have emerged as a potent source of DNA damage and genomic instability. The termination of defective RNA polymerase II (RNAPII) is one of the major sources of R-loop formation. 5'-3'-exoribonuclease 2 (XRN2) promotes genome-wide efficient RNAPII termination, and XRN2-deficient cells exhibit increased DNA damage emanating from elevated R-loops. Recently, we showed that DNA damage instigated by XRN2 depletion in human fibroblast cells resulted in enhanced poly(ADP-ribose) polymerase 1 (PARP1) activity. Additionally, we established a synthetic lethal relationship between XRN2 and PARP1. However, the underlying cellular stress response promoting this synthetic lethality remains elusive. Here, we delineate the molecular consequences leading to the synthetic lethality of XRN2-deficient cancer cells induced by PARP inhibition. We found that XRN2-deficient lung and breast cancer cells display sensitivity to two clinically relevant PARP inhibitors, Rucaparib and Olaparib. At a mechanistic level, PARP inhibition combined with XRN2 deficiency exacerbates R-loop and DNA double-strand break formation in cancer cells. Consistent with our previous findings using several different siRNAs, we also show that XRN2 deficiency in cancer cells hyperactivates PARP1. Furthermore, we observed enhanced replication stress in XRN2-deficient cancer cells treated with PARP inhibitors. Finally, the enhanced stress response instigated by compromised PARP1 catalytic function in XRN2-deficient cells activates caspase-3 to initiate cell death. Collectively, these findings provide mechanistic insights into the sensitivity of XRN2-deficient cancer cells to PARP inhibition and strengthen the underlying translational implications for targeted therapy.
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Affiliation(s)
| | | | | | | | - Praveen L. Patidar
- Department of Chemistry, New Mexico Institute of Mining and Technology, Socorro, NM 87801, USA
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21
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Wollman AJM, Syeda AH, Howard JAL, Payne-Dwyer A, Leech A, Warecka D, Guy C, McGlynn P, Hawkins M, Leake MC. Tetrameric UvrD Helicase Is Located at the E. Coli Replisome due to Frequent Replication Blocks. J Mol Biol 2024; 436:168369. [PMID: 37977299 DOI: 10.1016/j.jmb.2023.168369] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 11/10/2023] [Accepted: 11/11/2023] [Indexed: 11/19/2023]
Abstract
DNA replication in all organisms must overcome nucleoprotein blocks to complete genome duplication. Accessory replicative helicases in Escherichia coli, Rep and UvrD, help remove these blocks and aid the re-initiation of replication. Mechanistic details of Rep function have emerged from recent live cell studies; however, the division of UvrD functions between its activities in DNA repair and role as an accessory helicase remain unclear in live cells. By integrating super-resolved single-molecule fluorescence microscopy with biochemical analysis, we find that UvrD self-associates into tetrameric assemblies and, unlike Rep, is not recruited to a specific replisome protein despite being found at approximately 80% of replication forks. Instead, its colocation with forks is likely due to the very high frequency of replication blocks composed of DNA-bound proteins, including RNA polymerase and factors involved in repairing DNA damage. Deleting rep and DNA repair factor genes mutS and uvrA, and inhibiting transcription through RNA polymerase mutation and antibiotic inhibition, indicates that the level of UvrD at the fork is dependent on UvrD's function. Our findings show that UvrD is recruited to sites of nucleoprotein blocks via different mechanisms to Rep and plays a multi-faceted role in ensuring successful DNA replication.
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Affiliation(s)
- Adam J M Wollman
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Aisha H Syeda
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Jamieson A L Howard
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Alex Payne-Dwyer
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Andrew Leech
- Bioscience Technology Facility, Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Dominika Warecka
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Colin Guy
- Covance Laboratories Ltd., Otley Road, Harrogate HG3 1PY, United Kingdom
| | - Peter McGlynn
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Michelle Hawkins
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Mark C Leake
- School of Physics, Engineering and Technology, University of York, York YO10 5DD, United Kingdom; Department of Biology, University of York, York YO10 5DD, United Kingdom.
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22
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Yang Y, Badura ML, O’Leary PC, Delavan HM, Robinson TM, Egusa EA, Zhong X, Swinderman JT, Li H, Zhang M, Kim M, Ashworth A, Feng FY, Chou J, Yang L. Large tandem duplications in cancer result from transcription and DNA replication collisions. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2023.05.17.23290140. [PMID: 38260434 PMCID: PMC10802642 DOI: 10.1101/2023.05.17.23290140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Despite the abundance of somatic structural variations (SVs) in cancer, the underlying molecular mechanisms of their formation remain unclear. Here, we use 6,193 whole-genome sequenced tumors to study the contributions of transcription and DNA replication collisions to genome instability. After deconvoluting robust SV signatures in three independent pan-cancer cohorts, we detect transcription-dependent replicated-strand bias, the expected footprint of transcription-replication collision (TRC), in large tandem duplications (TDs). Large TDs are abundant in female-enriched, upper gastrointestinal tract and prostate cancers. They are associated with poor patient survival and mutations in TP53, CDK12, and SPOP. Upon inactivating CDK12, cells display significantly more TRCs, R-loops, and large TDs. Inhibition of G2/M checkpoint proteins, such as WEE1, CHK1, and ATR, selectively inhibits the growth of cells deficient in CDK12. Our data suggest that large TDs in cancer form due to TRCs, and their presence can be used as a biomarker for prognosis and treatment.
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Affiliation(s)
- Yang Yang
- Ben May Department for Cancer Research, University of Chicago, Chicago, IL, USA
| | - Michelle L. Badura
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
- Departments of Radiation Oncology and Urology, University of California, San Francisco, CA, USA
| | - Patrick C. O’Leary
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
| | - Henry M. Delavan
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
- Division of Hematology/Oncology, Department of Medicine, University of California, San Francisco, CA, USA
| | - Troy M. Robinson
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
- Departments of Radiation Oncology and Urology, University of California, San Francisco, CA, USA
| | - Emily A. Egusa
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
- Departments of Radiation Oncology and Urology, University of California, San Francisco, CA, USA
| | - Xiaoming Zhong
- Ben May Department for Cancer Research, University of Chicago, Chicago, IL, USA
| | - Jason T. Swinderman
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
- Departments of Radiation Oncology and Urology, University of California, San Francisco, CA, USA
| | - Haolong Li
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
- Departments of Radiation Oncology and Urology, University of California, San Francisco, CA, USA
| | - Meng Zhang
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
- Departments of Radiation Oncology and Urology, University of California, San Francisco, CA, USA
| | - Minkyu Kim
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
- Department of Cellular Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA
| | - Alan Ashworth
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
- Division of Hematology/Oncology, Department of Medicine, University of California, San Francisco, CA, USA
| | - Felix Y. Feng
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
- Departments of Radiation Oncology and Urology, University of California, San Francisco, CA, USA
- Division of Hematology/Oncology, Department of Medicine, University of California, San Francisco, CA, USA
| | - Jonathan Chou
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, USA
- Division of Hematology/Oncology, Department of Medicine, University of California, San Francisco, CA, USA
| | - Lixing Yang
- Ben May Department for Cancer Research, University of Chicago, Chicago, IL, USA
- Department of Human Genetics, University of Chicago, Chicago, IL, USA
- University of Chicago Comprehensive Cancer Center, Chicago, IL, USA
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23
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Milano L, Gautam A, Caldecott KW. DNA damage and transcription stress. Mol Cell 2024; 84:70-79. [PMID: 38103560 DOI: 10.1016/j.molcel.2023.11.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/10/2023] [Accepted: 11/15/2023] [Indexed: 12/19/2023]
Abstract
Genome damage and transcription are intimately linked. Tens to hundreds of thousands of DNA lesions arise in each cell each day, many of which can directly or indirectly impede transcription. Conversely, the process of gene expression is itself a source of endogenous DNA lesions as a result of the susceptibility of single-stranded DNA to damage, conflicts with the DNA replication machinery, and engagement by cells of topoisomerases and base excision repair enzymes to regulate the initiation and progression of gene transcription. Although such processes are tightly regulated and normally accurate, on occasion, they can become abortive and leave behind DNA breaks that can drive genome rearrangements, instability, or cell death.
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Affiliation(s)
- Larissa Milano
- Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
| | - Amit Gautam
- Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
| | - Keith W Caldecott
- Genome Damage and Stability Centre, University of Sussex, Falmer, Brighton BN1 9RQ, UK.
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24
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Kumar C, Remus D. Looping out of control: R-loops in transcription-replication conflict. Chromosoma 2024; 133:37-56. [PMID: 37419963 PMCID: PMC10771546 DOI: 10.1007/s00412-023-00804-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 06/27/2023] [Accepted: 06/28/2023] [Indexed: 07/09/2023]
Abstract
Transcription-replication conflict is a major cause of replication stress that arises when replication forks collide with the transcription machinery. Replication fork stalling at sites of transcription compromises chromosome replication fidelity and can induce DNA damage with potentially deleterious consequences for genome stability and organismal health. The block to DNA replication by the transcription machinery is complex and can involve stalled or elongating RNA polymerases, promoter-bound transcription factor complexes, or DNA topology constraints. In addition, studies over the past two decades have identified co-transcriptional R-loops as a major source for impairment of DNA replication forks at active genes. However, how R-loops impede DNA replication at the molecular level is incompletely understood. Current evidence suggests that RNA:DNA hybrids, DNA secondary structures, stalled RNA polymerases, and condensed chromatin states associated with R-loops contribute to the of fork progression. Moreover, since both R-loops and replication forks are intrinsically asymmetric structures, the outcome of R-loop-replisome collisions is influenced by collision orientation. Collectively, the data suggest that the impact of R-loops on DNA replication is highly dependent on their specific structural composition. Here, we will summarize our current understanding of the molecular basis for R-loop-induced replication fork progression defects.
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Affiliation(s)
- Charanya Kumar
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York, 10065, USA
| | - Dirk Remus
- Molecular Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York, 10065, USA.
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25
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Yang KB, Rasouly A, Epshtein V, Martinez C, Nguyen T, Shamovsky I, Nudler E. Persistence of backtracking by human RNA polymerase II. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.13.571520. [PMID: 38168453 PMCID: PMC10760130 DOI: 10.1101/2023.12.13.571520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
RNA polymerase II (pol II) can backtrack during transcription elongation, exposing the 3' end of nascent RNA. Nascent RNA sequencing can approximate the location of backtracking events that are quickly resolved; however, the extent and genome wide distribution of more persistent backtracking is unknown. Consequently, we developed a novel method to directly sequence the extruded, "backtracked" 3' RNA. Our data shows that pol II slides backwards more than 20 nucleotides in human cells and can persist in this backtracked state. Persistent backtracking mainly occurs where pol II pauses near promoters and intron-exon junctions, and is enriched in genes involved in translation, replication, and development, where gene expression is decreased if these events are unresolved. Histone genes are highly prone to persistent backtracking, and the resolution of such events is likely required for timely expression during cell division. These results demonstrate that persistent backtracking has the potential to affect diverse gene expression programs.
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Irony-Tur Sinai M, Kerem B. Insights into common fragile site instability: DNA replication challenges at DNA repeat sequences. Emerg Top Life Sci 2023; 7:277-287. [PMID: 37876349 PMCID: PMC10754330 DOI: 10.1042/etls20230023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 10/08/2023] [Accepted: 10/12/2023] [Indexed: 10/26/2023]
Abstract
Common fragile sites (CFS) are specific genomic regions prone to chromosomal instability under conditions of DNA replication stress. CFSs manifest as breaks, gaps, and constrictions on metaphase chromosomes under mild replication stress. These replication-sensitive CFS regions are preferentially unstable during cancer development, as reflected by their association with copy number variants (CNVs) frequently arise in most tumor types. Over the years, it became clear that a combination of different characteristics underlies the enhanced sensitivity of CFSs to replication stress. As of today, there is a strong evidence that the core fragility regions along CFSs overlap with actively transcribed large genes with delayed replication timing upon replication stress. Recently, the mechanistic basis for CFS instability was further extended to regions which span topologically associated domain (TAD) boundaries, generating a fragility signature composed of replication, transcription and genome organization. The presence of difficult-to-replicate AT-rich repeats was one of the early features suggested to characterize a subgroup of CFSs. These long stretches of AT-dinucleotide have the potential to fold into stable secondary structures which may impede replication fork progression, leaving the region under-replicated. Here, we focus on the molecular mechanisms underlying repeat instability at CFSs and on the proteins involved in the resolution of secondary structure impediments arising along repetitive sequence elements which are essential for the maintenance of genome stability.
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Affiliation(s)
- Michal Irony-Tur Sinai
- Department of Genetics, The Life Sciences Institute, The Hebrew University, Jerusalem, Israel
| | - Batsheva Kerem
- Department of Genetics, The Life Sciences Institute, The Hebrew University, Jerusalem, Israel
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27
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Jaiswal AS, Dutta A, Srinivasan G, Yuan Y, Zhou D, Shaheen M, Sadideen D, Kirby A, Williamson E, Gupta Y, Olsen SK, Xu M, Loranc E, Mukhopadhyay P, Pertsemlidis A, Bishop AR, Sung P, Nickoloff J, Hromas R. TATDN2 resolution of R-loops is required for survival of BRCA1-mutant cancer cells. Nucleic Acids Res 2023; 51:12224-12241. [PMID: 37953292 PMCID: PMC10711561 DOI: 10.1093/nar/gkad952] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 10/03/2023] [Accepted: 10/18/2023] [Indexed: 11/14/2023] Open
Abstract
BRCA1-deficient cells have increased IRE1 RNase, which degrades multiple microRNAs. Reconstituting expression of one of these, miR-4638-5p, resulted in synthetic lethality in BRCA1-deficient cancer cells. We found that miR-4638-5p represses expression of TATDN2, a poorly characterized member of the TATD nuclease family. We discovered that human TATDN2 has RNA 3' exonuclease and endonuclease activity on double-stranded hairpin RNA structures. Given the cleavage of hairpin RNA by TATDN2, and that BRCA1-deficient cells have difficulty resolving R-loops, we tested whether TATDN2 could resolve R-loops. Using in vitro biochemical reconstitution assays, we found TATDN2 bound to R-loops and degraded the RNA strand but not DNA of multiple forms of R-loops in vitro in a Mg2+-dependent manner. Mutations in amino acids E593 and E705 predicted by Alphafold-2 to chelate an essential Mg2+ cation completely abrogated this R-loop resolution activity. Depleting TATDN2 increased cellular R-loops, DNA damage and chromosomal instability. Loss of TATDN2 resulted in poor replication fork progression in the presence of increased R-loops. Significantly, we found that TATDN2 is essential for survival of BRCA1-deficient cancer cells, but much less so for cognate BRCA1-repleted cancer cells. Thus, we propose that TATDN2 is a novel target for therapy of BRCA1-deficient cancers.
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Affiliation(s)
- Aruna S Jaiswal
- Department of Medicine and the Mays Cancer Center, the University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
| | - Arijit Dutta
- Department of Biochemistry and Structural Biology and the Greehey Children's Cancer Research Institute, the University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
| | - Gayathri Srinivasan
- Department of Medicine and the Mays Cancer Center, the University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
| | - Yaxia Yuan
- Department of Biochemistry and Structural Biology and the Greehey Children's Cancer Research Institute, the University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
| | - Daohong Zhou
- Department of Biochemistry and Structural Biology and the Greehey Children's Cancer Research Institute, the University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
| | - Montaser Shaheen
- Department of Medicine and the Mays Cancer Center, the University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
| | - Doraid T Sadideen
- Department of Medicine and the Mays Cancer Center, the University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
| | - Austin Kirby
- Department of Medicine and the Mays Cancer Center, the University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
| | - Elizabeth A Williamson
- Department of Medicine and the Mays Cancer Center, the University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
| | - Yogesh K Gupta
- Department of Biochemistry and Structural Biology and the Greehey Children's Cancer Research Institute, the University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
| | - Shaun K Olsen
- Department of Biochemistry and Structural Biology and the Greehey Children's Cancer Research Institute, the University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
| | - Mingjiang Xu
- Department of Molecular Medicine and the Mays Cancer Center, the University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
| | - Eva Loranc
- Department of Cell Systems and Anatomy and the Greehey Children's Cancer Research Institute, the University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
| | - Pramiti Mukhopadhyay
- Department of Cell Systems and Anatomy and the Greehey Children's Cancer Research Institute, the University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
| | - Alexander Pertsemlidis
- Department of Cell Systems and Anatomy and the Greehey Children's Cancer Research Institute, the University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
| | - Alexander J R Bishop
- Department of Cell Systems and Anatomy and the Greehey Children's Cancer Research Institute, the University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
| | - Patrick Sung
- Department of Biochemistry and Structural Biology and the Greehey Children's Cancer Research Institute, the University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
| | - Jac A Nickoloff
- Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Robert Hromas
- Department of Medicine and the Mays Cancer Center, the University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA
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28
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Nickoloff JA, Jaiswal AS, Sharma N, Williamson EA, Tran MT, Arris D, Yang M, Hromas R. Cellular Responses to Widespread DNA Replication Stress. Int J Mol Sci 2023; 24:16903. [PMID: 38069223 PMCID: PMC10707325 DOI: 10.3390/ijms242316903] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/22/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Replicative DNA polymerases are blocked by nearly all types of DNA damage. The resulting DNA replication stress threatens genome stability. DNA replication stress is also caused by depletion of nucleotide pools, DNA polymerase inhibitors, and DNA sequences or structures that are difficult to replicate. Replication stress triggers complex cellular responses that include cell cycle arrest, replication fork collapse to one-ended DNA double-strand breaks, induction of DNA repair, and programmed cell death after excessive damage. Replication stress caused by specific structures (e.g., G-rich sequences that form G-quadruplexes) is localized but occurs during the S phase of every cell division. This review focuses on cellular responses to widespread stress such as that caused by random DNA damage, DNA polymerase inhibition/nucleotide pool depletion, and R-loops. Another form of global replication stress is seen in cancer cells and is termed oncogenic stress, reflecting dysregulated replication origin firing and/or replication fork progression. Replication stress responses are often dysregulated in cancer cells, and this too contributes to ongoing genome instability that can drive cancer progression. Nucleases play critical roles in replication stress responses, including MUS81, EEPD1, Metnase, CtIP, MRE11, EXO1, DNA2-BLM, SLX1-SLX4, XPF-ERCC1-SLX4, Artemis, XPG, FEN1, and TATDN2. Several of these nucleases cleave branched DNA structures at stressed replication forks to promote repair and restart of these forks. We recently defined roles for EEPD1 in restarting stressed replication forks after oxidative DNA damage, and for TATDN2 in mitigating replication stress caused by R-loop accumulation in BRCA1-defective cells. We also discuss how insights into biological responses to genome-wide replication stress can inform novel cancer treatment strategies that exploit synthetic lethal relationships among replication stress response factors.
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Affiliation(s)
- Jac A. Nickoloff
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Aruna S. Jaiswal
- Department of Medicine and the Mays Cancer Center, The University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (A.S.J.); (M.T.T.); (R.H.)
| | - Neelam Sharma
- Department of Environmental and Radiological Health Sciences, Colorado State University, Ft. Collins, CO 80523, USA
| | - Elizabeth A. Williamson
- Department of Medicine and the Mays Cancer Center, The University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (A.S.J.); (M.T.T.); (R.H.)
| | - Manh T. Tran
- Department of Medicine and the Mays Cancer Center, The University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (A.S.J.); (M.T.T.); (R.H.)
| | - Dominic Arris
- Department of Medicine and the Mays Cancer Center, The University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (A.S.J.); (M.T.T.); (R.H.)
| | - Ming Yang
- Department of Medicine and the Mays Cancer Center, The University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (A.S.J.); (M.T.T.); (R.H.)
| | - Robert Hromas
- Department of Medicine and the Mays Cancer Center, The University of Texas Health Science Center San Antonio, San Antonio, TX 78229, USA; (A.S.J.); (M.T.T.); (R.H.)
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29
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Li Q, Zhou J, Li S, Zhang W, Du Y, Li K, Wang Y, Sun Q. DNA polymerase ε harmonizes topological states and R-loops formation to maintain genome integrity in Arabidopsis. Nat Commun 2023; 14:7763. [PMID: 38012183 PMCID: PMC10682485 DOI: 10.1038/s41467-023-43680-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 11/16/2023] [Indexed: 11/29/2023] Open
Abstract
Genome topology is tied to R-loop formation and genome stability. However, the regulatory mechanism remains to be elucidated. By establishing a system to sense the connections between R-loops and genome topology states, we show that inhibiting DNA topoisomerase 1 (TOP1i) triggers the global increase of R-loops (called topoR-loops) and DNA damages, which are exacerbated in the DNA damage repair-compromised mutant atm. A suppressor screen identifies a mutation in POL2A, the catalytic subunit of DNA polymerase ε, rescuing the TOP1i-induced topoR-loop accumulation and genome instability in atm. Importantly we find that a highly conserved junction domain between the exonuclease and polymerase domains in POL2A is required for modulating topoR-loops near DNA replication origins and facilitating faithful DNA replication. Our results suggest that DNA replication acts in concert with genome topological states to fine-tune R-loops and thereby maintain genome integrity, revealing a likely conserved regulatory mechanism of TOP1i resistance in chemotherapy for ATM-deficient cancers.
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Affiliation(s)
- Qin Li
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Jincong Zhou
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China
| | - Shuai Li
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China
| | - Weifeng Zhang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China
| | - Yingxue Du
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China
| | - Kuan Li
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China
- Chinese Institute for Brain Research, Beijing, 102206, China
| | - Yingxiang Wang
- College of Life Science, South China Agricultural University, Guangdong Laboratory for Lingnan Morden Agriculture, Guangzhou, 510642, China
- State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Qianwen Sun
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
- Tsinghua-Peking Center for Life Sciences, Beijing, 100084, China.
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30
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Abstract
Transcription and replication both require large macromolecular complexes to act on a DNA template, yet these machineries cannot simultaneously act on the same DNA sequence. Conflicts between the replication and transcription machineries (transcription-replication conflicts, or TRCs) are widespread in both prokaryotes and eukaryotes and have the capacity to both cause DNA damage and compromise complete, faithful replication of the genome. This review will highlight recent studies investigating the genomic locations of TRCs and the mechanisms by which they may be prevented, mitigated, or resolved. We address work from both model organisms and mammalian systems but predominantly focus on multicellular eukaryotes owing to the additional complexities inherent in the coordination of replication and transcription in the context of cell type-specific gene expression and higher-order chromatin organization.
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Affiliation(s)
- Liana Goehring
- Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY, USA;
| | - Tony T Huang
- Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, NY, USA;
| | - Duncan J Smith
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY, USA;
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31
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Duardo RC, Guerra F, Pepe S, Capranico G. Non-B DNA structures as a booster of genome instability. Biochimie 2023; 214:176-192. [PMID: 37429410 DOI: 10.1016/j.biochi.2023.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 07/04/2023] [Accepted: 07/06/2023] [Indexed: 07/12/2023]
Abstract
Non-canonical secondary structures (NCSs) are alternative nucleic acid structures that differ from the canonical B-DNA conformation. NCSs often occur in repetitive DNA sequences and can adopt different conformations depending on the sequence. The majority of these structures form in the context of physiological processes, such as transcription-associated R-loops, G4s, as well as hairpins and slipped-strand DNA, whose formation can be dependent on DNA replication. It is therefore not surprising that NCSs play important roles in the regulation of key biological processes. In the last years, increasing published data have supported their biological role thanks to genome-wide studies and the development of bioinformatic prediction tools. Data have also highlighted the pathological role of these secondary structures. Indeed, the alteration or stabilization of NCSs can cause the impairment of transcription and DNA replication, modification in chromatin structure and DNA damage. These events lead to a wide range of recombination events, deletions, mutations and chromosomal aberrations, well-known hallmarks of genome instability which are strongly associated with human diseases. In this review, we summarize molecular processes through which NCSs trigger genome instability, with a focus on G-quadruplex, i-motif, R-loop, Z-DNA, hairpin, cruciform and multi-stranded structures known as triplexes.
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Affiliation(s)
- Renée C Duardo
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Federico Guerra
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Simona Pepe
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum University of Bologna, via Selmi 3, 40126, Bologna, Italy
| | - Giovanni Capranico
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum University of Bologna, via Selmi 3, 40126, Bologna, Italy.
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32
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Bhowmick R, Hickson ID, Liu Y. Completing genome replication outside of S phase. Mol Cell 2023; 83:3596-3607. [PMID: 37716351 DOI: 10.1016/j.molcel.2023.08.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 08/03/2023] [Accepted: 08/17/2023] [Indexed: 09/18/2023]
Abstract
Mitotic DNA synthesis (MiDAS) is an unusual form of DNA replication that occurs during mitosis. Initially, MiDAS was characterized as a process associated with intrinsically unstable loci known as common fragile sites that occurs after cells experience DNA replication stress (RS). However, it is now believed to be a more widespread "salvage" mechanism that is called upon to complete the duplication of any under-replicated genomic region. Emerging data suggest that MiDAS is a DNA repair process potentially involving two or more pathways working in parallel or sequentially. In this review, we introduce the causes of RS, regions of the human genome known to be especially vulnerable to RS, and the strategies used to complete DNA replication outside of S phase. Additionally, because MiDAS is a prominent feature of aneuploid cancer cells, we will discuss how targeting MiDAS might potentially lead to improvements in cancer therapy.
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Affiliation(s)
- Rahul Bhowmick
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, Blegdamsvej 3B, 2200 Copenhagen N, Denmark; Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Ian D Hickson
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, Blegdamsvej 3B, 2200 Copenhagen N, Denmark.
| | - Ying Liu
- Center for Chromosome Stability and Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Panum Institute, Blegdamsvej 3B, 2200 Copenhagen N, Denmark.
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33
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Wang N, Xu S, Egli D. Replication stress in mammalian embryo development, differentiation, and reprogramming. Trends Cell Biol 2023; 33:872-886. [PMID: 37202286 PMCID: PMC11214770 DOI: 10.1016/j.tcb.2023.03.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 03/24/2023] [Accepted: 03/29/2023] [Indexed: 05/20/2023]
Abstract
Duplicating a genome of 3 billion nucleotides is challenged by a variety of obstacles that can cause replication stress and affect the integrity of the genome. Recent studies show that replication fork slowing and stalling is prevalent in early mammalian development, resulting in genome instability and aneuploidy, and constituting a barrier to development in human reproduction. Genome instability resulting from DNA replication stress is a barrier to the cloning of animals and to the reprogramming of differentiated cells to induced pluripotent stem cells, as well as a barrier to cell transformation. Remarkably, the regions most impacted by replication stress are shared in these different cellular contexts, affecting long genes and flanking intergenic areas. In this review we integrate our knowledge of DNA replication stress in mammalian embryos, in programming, and in reprogramming, and we discuss a potential role for fragile sites in sensing replication stress and restricting cell cycle progression in health and disease.
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Affiliation(s)
- Ning Wang
- Division of Molecular Genetics, Department of Pediatrics and Naomi Berrie Diabetes Center, Columbia Stem Cell Initiative, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Shuangyi Xu
- Division of Molecular Genetics, Department of Pediatrics and Naomi Berrie Diabetes Center, Columbia Stem Cell Initiative, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Dieter Egli
- Division of Molecular Genetics, Department of Pediatrics and Naomi Berrie Diabetes Center, Columbia Stem Cell Initiative, Columbia University Irving Medical Center, New York, NY 10032, USA.
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Mo C, Shiozaki Y, Omabe K, Liu Y. Understanding the Human RECQ5 Helicase-Connecting the Dots from DNA to Clinics. Cells 2023; 12:2037. [PMID: 37626846 PMCID: PMC10453775 DOI: 10.3390/cells12162037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 08/03/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023] Open
Abstract
RECQ5, a member of the conserved RECQ helicase family, is the sole human RECQ homolog that has not been linked to a hereditary developmental syndrome. Nonetheless, dysregulation of RECQ5 has emerged as a significant clinical concern, being linked to cancer predisposition, cardiovascular disease, and inflammation. In cells, RECQ5 assumes a crucial role in the regulation of DNA repair pathways, particularly in the repair of DNA double-strand breaks and inter-strand DNA crosslinks. Moreover, RECQ5 exhibits a capacity to modulate gene expression by interacting with transcription machineries and their co-regulatory proteins, thus safeguarding against transcription-induced DNA damage. This review aims to provide an overview of the multifaceted functions of RECQ5 and its implications in maintaining genomic stability. We will discuss the potential effects of clinical variants of RECQ5 on its cellular functions and their underlying mechanisms in the pathogenesis of cancer and cardiovascular disease. We will review the impact of RECQ5 variants in the field of pharmacogenomics, specifically their influence on drug responses, which may pave the way for novel therapeutic interventions targeting RECQ5 in human diseases.
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Affiliation(s)
| | | | | | - Yilun Liu
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute of City of Hope, 1500 East Duarte Road, Duarte, CA 91010-3000, USA
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35
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Fenstermaker TK, Petruk S, Kovermann SK, Brock HW, Mazo A. RNA polymerase II associates with active genes during DNA replication. Nature 2023; 620:426-433. [PMID: 37468626 DOI: 10.1038/s41586-023-06341-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 06/19/2023] [Indexed: 07/21/2023]
Abstract
The transcriptional machinery is thought to dissociate from DNA during replication. Certain proteins, termed epigenetic marks, must be transferred from parent to daughter DNA strands in order to maintain the memory of transcriptional states1,2. These proteins are believed to re-initiate rebuilding of chromatin structure, which ultimately recruits RNA polymerase II (Pol II) to the newly replicated daughter strands. It is believed that Pol II is recruited back to active genes only after chromatin is rebuilt3,4. However, there is little experimental evidence addressing the central questions of when and how Pol II is recruited back to the daughter strands and resumes transcription. Here we show that immediately after passage of the replication fork, Pol II in complex with other general transcription proteins and immature RNA re-associates with active genes on both leading and lagging strands of nascent DNA, and rapidly resumes transcription. This suggests that the transcriptionally active Pol II complex is retained in close proximity to DNA, with a Pol II-PCNA interaction potentially underlying this retention. These findings indicate that the Pol II machinery may not require epigenetic marks to be recruited to the newly synthesized DNA during the transition from DNA replication to resumption of transcription.
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Affiliation(s)
- Tyler K Fenstermaker
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Svetlana Petruk
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Sina K Kovermann
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Hugh W Brock
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Alexander Mazo
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA.
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36
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Krachmarova E, Petkov P, Lilkova E, Ilieva N, Rangelov M, Todorova N, Malinova K, Hristova R, Nacheva G, Gospodinov A, Litov L. Insights into the SARS-CoV-2 ORF6 Mechanism of Action. Int J Mol Sci 2023; 24:11589. [PMID: 37511350 PMCID: PMC10380535 DOI: 10.3390/ijms241411589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 07/10/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
ORF6 is responsible for suppressing the immune response of cells infected by the SARS-CoV-2 virus. It is also the most toxic protein of SARS-CoV-2, and its actions are associated with the viral pathogenicity. Here, we study in silico and in vitro the structure of the protein, its interaction with RAE1 and the mechanism of action behind its high toxicity. We show both computationally and experimentally that SARS-CoV-2 ORF6, embedded in the cytoplasmic membranes, binds to RAE1 and sequesters it in the cytoplasm, thus depleting its availability in the nucleus and impairing nucleocytoplasmic mRNA transport. This negatively affects the cellular genome stability by compromising the cell cycle progression into the S-phase and by promoting the accumulation of RNA-DNA hybrids. Understanding the multiple ways in which ORF6 affects DNA replication may also have important implications for elucidating the pathogenicity of SARS-CoV-2 and developing therapeutic strategies to mitigate its deleterious effects on host cells.
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Affiliation(s)
- Elena Krachmarova
- Institute of Molecular Biology “Acad. Roumen Tsanev”, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (E.K.); (K.M.); (R.H.); (G.N.)
| | - Peicho Petkov
- Faculty of Physics, Sofia University “St. Kliment Ohridski”, 1164 Sofia, Bulgaria;
| | - Elena Lilkova
- Institute of Information and Communication Technologies, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (E.L.); (N.I.)
| | - Nevena Ilieva
- Institute of Information and Communication Technologies, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (E.L.); (N.I.)
| | - Miroslav Rangelov
- Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria;
| | - Nadezhda Todorova
- Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria;
| | - Kristina Malinova
- Institute of Molecular Biology “Acad. Roumen Tsanev”, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (E.K.); (K.M.); (R.H.); (G.N.)
| | - Rossitsa Hristova
- Institute of Molecular Biology “Acad. Roumen Tsanev”, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (E.K.); (K.M.); (R.H.); (G.N.)
| | - Genoveva Nacheva
- Institute of Molecular Biology “Acad. Roumen Tsanev”, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (E.K.); (K.M.); (R.H.); (G.N.)
| | - Anastas Gospodinov
- Institute of Molecular Biology “Acad. Roumen Tsanev”, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (E.K.); (K.M.); (R.H.); (G.N.)
| | - Leandar Litov
- Faculty of Physics, Sofia University “St. Kliment Ohridski”, 1164 Sofia, Bulgaria;
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37
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Hao N, Donnelly AJ, Dodd IB, Shearwin KE. When push comes to shove - RNA polymerase and DNA-bound protein roadblocks. Biophys Rev 2023; 15:355-366. [PMID: 37396453 PMCID: PMC10310618 DOI: 10.1007/s12551-023-01064-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 05/21/2023] [Indexed: 07/04/2023] Open
Abstract
In recent years, transcriptional roadblocking has emerged as a crucial regulatory mechanism in gene expression, whereby other DNA-bound obstacles can block the progression of transcribing RNA polymerase (RNAP), leading to RNAP pausing and ultimately dissociation from the DNA template. In this review, we discuss the mechanisms by which transcriptional roadblocks can impede RNAP progression, as well as how RNAP can overcome these obstacles to continue transcription. We examine different DNA-binding proteins involved in transcriptional roadblocking and their biophysical properties that determine their effectiveness in blocking RNAP progression. The catalytically dead CRISPR-Cas (dCas) protein is used as an example of an engineered programmable roadblock, and the current literature in understanding the polarity of dCas roadblocking is also discussed. Finally, we delve into a stochastic model of transcriptional roadblocking and highlight the importance of transcription factor binding kinetics and its resistance to dislodgement by an elongating RNAP in determining the strength of a roadblock.
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Affiliation(s)
- Nan Hao
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005 Australia
| | - Alana J. Donnelly
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005 Australia
| | - Ian B. Dodd
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005 Australia
| | - Keith E. Shearwin
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, SA 5005 Australia
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38
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Hill HJ, Bonser D, Golic KG. Dicentric chromosome breakage in Drosophila melanogaster is influenced by pericentric heterochromatin and occurs in nonconserved hotspots. Genetics 2023; 224:iyad052. [PMID: 37010100 PMCID: PMC10213500 DOI: 10.1093/genetics/iyad052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 10/18/2022] [Accepted: 03/13/2023] [Indexed: 04/04/2023] Open
Abstract
Chromosome breakage plays an important role in the evolution of karyotypes and can produce deleterious effects within a single individual, such as aneuploidy or cancer. Forces that influence how and where chromosomes break are not fully understood. In humans, breakage tends to occur in conserved hotspots called common fragile sites (CFS), especially during replication stress. By following the fate of dicentric chromosomes in Drosophila melanogaster, we find that breakage under tension also tends to occur in specific hotspots. Our experimental approach was to induce sister chromatid exchange in a ring chromosome to generate a dicentric chromosome with a double chromatid bridge. In the following cell division, the dicentric bridges may break. We analyzed the breakage patterns of 3 different ring-X chromosomes. These chromosomes differ by the amount and quality of heterochromatin they carry as well as their genealogical history. For all 3 chromosomes, breakage occurs preferentially in several hotspots. Surprisingly, we found that the hotspot locations are not conserved between the 3 chromosomes: each displays a unique array of breakage hotspots. The lack of hotspot conservation, along with a lack of response to aphidicolin, suggests that these breakage sites are not entirely analogous to CFS and may reveal new mechanisms of chromosome fragility. Additionally, the frequency of dicentric breakage and the durability of each chromosome's spindle attachment vary significantly between the 3 chromosomes and are correlated with the origin of the centromere and the amount of pericentric heterochromatin. We suggest that different centromere strengths could account for this.
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Affiliation(s)
- Hunter J Hill
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Danielle Bonser
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Kent G Golic
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
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39
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Gong Y, Liu Y. R-Loops at Chromosome Ends: From Formation, Regulation, and Cellular Consequence. Cancers (Basel) 2023; 15:cancers15072178. [PMID: 37046839 PMCID: PMC10093737 DOI: 10.3390/cancers15072178] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 04/03/2023] [Accepted: 04/04/2023] [Indexed: 04/14/2023] Open
Abstract
Telomeric repeat containing RNA (TERRA) is transcribed from subtelomeric regions to telomeres. TERRA RNA can invade telomeric dsDNA and form telomeric R-loop structures. A growing body of evidence suggests that TERRA-mediated R-loops are critical players in telomere length homeostasis. Here, we will review current knowledge on the regulation of R-loop levels at telomeres. In particular, we will discuss how the central player TERRA and its binding proteins modulate R-loop levels through various mechanisms. We will further provide an overview of the consequences of TERRA-mediated persistent or unscheduled R-loops at telomeres in human ALT cancers and other organisms, with a focus on telomere length regulation after replication interference-induced damage and DNA homologous recombination-mediated repair.
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Affiliation(s)
- Yi Gong
- Laboratory of Genetics and Genomics, National Institute on Aging/National Institutes of Health, 251 Bayview Blvd, Baltimore, MD 21224, USA
| | - Yie Liu
- Laboratory of Genetics and Genomics, National Institute on Aging/National Institutes of Health, 251 Bayview Blvd, Baltimore, MD 21224, USA
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40
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Wang G, Vasquez KM. Dynamic alternative DNA structures in biology and disease. Nat Rev Genet 2023; 24:211-234. [PMID: 36316397 DOI: 10.1038/s41576-022-00539-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 55.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2022] [Indexed: 11/06/2022]
Abstract
Repetitive elements in the human genome, once considered 'junk DNA', are now known to adopt more than a dozen alternative (that is, non-B) DNA structures, such as self-annealed hairpins, left-handed Z-DNA, three-stranded triplexes (H-DNA) or four-stranded guanine quadruplex structures (G4 DNA). These dynamic conformations can act as functional genomic elements involved in DNA replication and transcription, chromatin organization and genome stability. In addition, recent studies have revealed a role for these alternative structures in triggering error-generating DNA repair processes, thereby actively enabling genome plasticity. As a driving force for genetic variation, non-B DNA structures thus contribute to both disease aetiology and evolution.
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Affiliation(s)
- Guliang Wang
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Paediatric Research Institute, Austin, TX, USA
| | - Karen M Vasquez
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Dell Paediatric Research Institute, Austin, TX, USA.
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41
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Andrs M, Stoy H, Boleslavska B, Chappidi N, Kanagaraj R, Nascakova Z, Menon S, Rao S, Oravetzova A, Dobrovolna J, Surendranath K, Lopes M, Janscak P. Excessive reactive oxygen species induce transcription-dependent replication stress. Nat Commun 2023; 14:1791. [PMID: 36997515 PMCID: PMC10063555 DOI: 10.1038/s41467-023-37341-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 03/10/2023] [Indexed: 04/03/2023] Open
Abstract
Elevated levels of reactive oxygen species (ROS) reduce replication fork velocity by causing dissociation of the TIMELESS-TIPIN complex from the replisome. Here, we show that ROS generated by exposure of human cells to the ribonucleotide reductase inhibitor hydroxyurea (HU) promote replication fork reversal in a manner dependent on active transcription and formation of co-transcriptional RNA:DNA hybrids (R-loops). The frequency of R-loop-dependent fork stalling events is also increased after TIMELESS depletion or a partial inhibition of replicative DNA polymerases by aphidicolin, suggesting that this phenomenon is due to a global replication slowdown. In contrast, replication arrest caused by HU-induced depletion of deoxynucleotides does not induce fork reversal but, if allowed to persist, leads to extensive R-loop-independent DNA breakage during S-phase. Our work reveals a link between oxidative stress and transcription-replication interference that causes genomic alterations recurrently found in human cancer.
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Affiliation(s)
- Martin Andrs
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Henriette Stoy
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Barbora Boleslavska
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
- Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Nagaraja Chappidi
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden, Dresden, Germany
| | - Radhakrishnan Kanagaraj
- Genome Engineering Laboratory, School of Life Sciences, University of Westminster, London, UK
- School of Life Sciences, University of Bedfordshire, Luton, UK
- Centre for Drug Discovery and Development, Sathyabama Institute of Science and Technology, Chennai, India
| | - Zuzana Nascakova
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Shruti Menon
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
- School of Medicine, University of California San Francisco (UCSF), San Francisco, CA, USA
| | - Satyajeet Rao
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Anna Oravetzova
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
- Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Jana Dobrovolna
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Kalpana Surendranath
- Genome Engineering Laboratory, School of Life Sciences, University of Westminster, London, UK
- Centre for Drug Discovery and Development, Sathyabama Institute of Science and Technology, Chennai, India
| | - Massimo Lopes
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland
| | - Pavel Janscak
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic.
- Institute of Molecular Cancer Research, University of Zurich, Zurich, Switzerland.
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Balboni B, Rinaldi F, Previtali V, Ciamarone A, Girotto S, Cavalli A. Novel Insights into RAD52’s Structure, Function, and Druggability for Synthetic Lethality and Innovative Anticancer Therapies. Cancers (Basel) 2023; 15:cancers15061817. [PMID: 36980703 PMCID: PMC10046612 DOI: 10.3390/cancers15061817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/08/2023] [Accepted: 03/14/2023] [Indexed: 03/19/2023] Open
Abstract
In recent years, the RAD52 protein has been highlighted as a mediator of many DNA repair mechanisms. While RAD52 was initially considered to be a non-essential auxiliary factor, its inhibition has more recently been demonstrated to be synthetically lethal in cancer cells bearing mutations and inactivation of specific intracellular pathways, such as homologous recombination. RAD52 is now recognized as a novel and critical pharmacological target. In this review, we comprehensively describe the available structural and functional information on RAD52. The review highlights the pathways in which RAD52 is involved and the approaches to RAD52 inhibition. We discuss the multifaceted role of this protein, which has a complex, dynamic, and functional 3D superstructural arrangement. This complexity reinforces the need to further investigate and characterize RAD52 to solve a challenging mechanistic puzzle and pave the way for a robust drug discovery campaign.
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Affiliation(s)
- Beatrice Balboni
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genoa, Italy
- Department of Pharmacy and Biotechnology, University of Bologna, via Belmeloro 6, 40126 Bologna, Italy
| | - Francesco Rinaldi
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genoa, Italy
- Department of Pharmacy and Biotechnology, University of Bologna, via Belmeloro 6, 40126 Bologna, Italy
| | - Viola Previtali
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genoa, Italy
| | - Andrea Ciamarone
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genoa, Italy
- Department of Pharmacy and Biotechnology, University of Bologna, via Belmeloro 6, 40126 Bologna, Italy
| | - Stefania Girotto
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genoa, Italy
- Structural Biophysics and Translational Pharmacology Facility, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genoa, Italy
- Correspondence: (S.G.); (A.C.); Tel.: +39-010-2896-983 (S.G.); +39-010-2897-403 (A.C.)
| | - Andrea Cavalli
- Computational and Chemical Biology, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genoa, Italy
- Department of Pharmacy and Biotechnology, University of Bologna, via Belmeloro 6, 40126 Bologna, Italy
- Correspondence: (S.G.); (A.C.); Tel.: +39-010-2896-983 (S.G.); +39-010-2897-403 (A.C.)
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43
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Yu Y, Xu W, Wen C, Zhao S, Li G, Liu R, Chen ZJ, Qin Y, Ma J, Yang Y, Zhao S. UBE2T resolves transcription-replication conflicts and protects common fragile sites in primordial germ cells. Cell Mol Life Sci 2023; 80:92. [PMID: 36928776 PMCID: PMC11072727 DOI: 10.1007/s00018-023-04733-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 02/04/2023] [Accepted: 02/22/2023] [Indexed: 03/18/2023]
Abstract
The proper development of primordial germ cells (PGCs) is an essential prerequisite for gametogenesis and mammalian fertility. The Fanconi anemia (FA) pathway functions in maintaining the development of PGCs. FANCT/UBE2T serves as an E2 ubiquitin-conjugating enzyme that ubiquitylates the FANCD2-FANCI complex to activate the FA pathway, but its role in the development of PGCs is not clear. In this study, we found that Ube2t knockout mice showed defects in PGC proliferation, leading to severe loss of germ cells after birth. Deletion of UBE2T exacerbated DNA damage and triggered the activation of the p53 pathway. We further demonstrated that UBE2T counteracted transcription-replication conflicts by resolving R-loops and stabilizing replication forks, and also protected common fragile sites by resolving R-loops in large genes and promoting mitotic DNA synthesis to maintain the genome stability of PGCs. Overall, these results provide new insights into the function and regulatory mechanisms of the FA pathway ensuring normal development of PGCs.
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Affiliation(s)
- Yongze Yu
- Center for Reproductive Medicine, Shandong University, Jinan, 250012, Shandong, China
- Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China
- Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China
- Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China
- Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China
- National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Weiwei Xu
- Center for Reproductive Medicine, Shandong University, Jinan, 250012, Shandong, China
- Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China
- Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China
- Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China
- Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China
- National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Canxin Wen
- Center for Reproductive Medicine, Shandong University, Jinan, 250012, Shandong, China
- Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China
- Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China
- Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China
- Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China
- National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Simin Zhao
- Center for Reproductive Medicine, Shandong University, Jinan, 250012, Shandong, China
- Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China
- Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China
- Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China
- Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China
- National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Guangyu Li
- Center for Reproductive Medicine, Shandong University, Jinan, 250012, Shandong, China
- Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China
- Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China
- Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China
- Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China
- National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Ran Liu
- Center for Reproductive Medicine, Shandong University, Jinan, 250012, Shandong, China
- Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China
- Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China
- Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China
- Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China
- National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Zi-Jiang Chen
- Center for Reproductive Medicine, Shandong University, Jinan, 250012, Shandong, China
- Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China
- Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China
- Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China
- Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China
- National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
- Research Unit of Gametogenesis and Health of ART-Offspring, Chinese Academy of Medical Sciences, Jinan, 250021, Shandong, China
- Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai, 200135, China
- Center for Reproductive Medicine, School of Medicine, Ren Ji Hospital, Shanghai Jiao Tong University, Shanghai, 200135, China
| | - Yingying Qin
- Center for Reproductive Medicine, Shandong University, Jinan, 250012, Shandong, China
- Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China
- Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China
- Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China
- Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China
- National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China
| | - Jinlong Ma
- Center for Reproductive Medicine, Shandong University, Jinan, 250012, Shandong, China.
- Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.
- Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.
- Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.
- Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.
- National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China.
| | - Yajuan Yang
- Center for Reproductive Medicine, Shandong University, Jinan, 250012, Shandong, China.
- Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.
- Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.
- Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.
- Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.
- National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China.
| | - Shidou Zhao
- Center for Reproductive Medicine, Shandong University, Jinan, 250012, Shandong, China.
- Key Laboratory of Reproductive Endocrinology of Ministry of Education, Shandong University, Jinan, 250012, Shandong, China.
- Shandong Key Laboratory of Reproductive Medicine, Jinan, 250012, Shandong, China.
- Shandong Provincial Clinical Research Center for Reproductive Health, Jinan, 250012, Shandong, China.
- Shandong Technology Innovation Center for Reproductive Health, Jinan, 250012, Shandong, China.
- National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Shandong University, Jinan, 250012, Shandong, China.
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Moeckel C, Zaravinos A, Georgakopoulos-Soares I. Strand Asymmetries Across Genomic Processes. Comput Struct Biotechnol J 2023; 21:2036-2047. [PMID: 36968020 PMCID: PMC10030826 DOI: 10.1016/j.csbj.2023.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 03/08/2023] [Accepted: 03/08/2023] [Indexed: 03/12/2023] Open
Abstract
Across biological systems, a number of genomic processes, including transcription, replication, DNA repair, and transcription factor binding, display intrinsic directionalities. These directionalities are reflected in the asymmetric distribution of nucleotides, motifs, genes, transposon integration sites, and other functional elements across the two complementary strands. Strand asymmetries, including GC skews and mutational biases, have shaped the nucleotide composition of diverse organisms. The investigation of strand asymmetries often serves as a method to understand underlying biological mechanisms, including protein binding preferences, transcription factor interactions, retrotransposition, DNA damage and repair preferences, transcription-replication collisions, and mutagenesis mechanisms. Research into this subject also enables the identification of functional genomic sites, such as replication origins and transcription start sites. Improvements in our ability to detect and quantify DNA strand asymmetries will provide insights into diverse functionalities of the genome, the contribution of different mutational mechanisms in germline and somatic mutagenesis, and our knowledge of genome instability and evolution, which all have significant clinical implications in human disease, including cancer. In this review, we describe key developments that have been made across the field of genomic strand asymmetries, as well as the discovery of associated mechanisms.
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Affiliation(s)
- Camille Moeckel
- Institute for Personalized Medicine, Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Apostolos Zaravinos
- Department of Life Sciences, European University Cyprus, Diogenis Str., 6, Nicosia 2404, Cyprus
- Cancer Genetics, Genomics and Systems Biology laboratory, Basic and Translational Cancer Research Center (BTCRC), Nicosia 1516, Cyprus
- Corresponding author at: Department of Life Sciences, European University Cyprus, Diogenis Str., 6, Nicosia 2404, Cyprus.
| | - Ilias Georgakopoulos-Soares
- Institute for Personalized Medicine, Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
- Corresponding author.
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45
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Mitotic DNA synthesis in response to replication stress requires the sequential action of DNA polymerases zeta and delta in human cells. Nat Commun 2023; 14:706. [PMID: 36759509 PMCID: PMC9911744 DOI: 10.1038/s41467-023-35992-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 01/11/2023] [Indexed: 02/11/2023] Open
Abstract
Oncogene activation creates DNA replication stress (RS) in cancer cells, which can generate under-replicated DNA regions (UDRs) that persist until cells enter mitosis. UDRs also have the potential to generate DNA bridges in anaphase cells or micronuclei in the daughter cells, which could promote genomic instability. To suppress such damaging changes to the genome, human cells have developed a strategy to conduct 'unscheduled' DNA synthesis in mitosis (termed MiDAS) that serves to rescue under-replicated loci. Previous studies have shown that MiDAS proceeds via a POLD3-dependent pathway that shows some features of break-induced replication. Here, we define how human cells utilize both DNA gap filling (REV1 and Pol ζ) and replicative (Pol δ) DNA polymerases to complete genome duplication following a perturbed S-phase. We present evidence for the existence of a polymerase-switch during MiDAS that is required for new DNA synthesis at UDRs. Moreover, we reveal that, upon oncogene activation, cancer cell survival is significantly compromised when REV1 is depleted, suggesting that REV1 inhibition might be a feasible approach for the treatment of some human cancers.
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46
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Mushtaq A, Mir US, Altaf M. Multifaceted functions of RNA-binding protein vigilin in gene silencing, genome stability, and autism-related disorders. J Biol Chem 2023; 299:102988. [PMID: 36758804 PMCID: PMC10011833 DOI: 10.1016/j.jbc.2023.102988] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/10/2023] Open
Abstract
RNA-binding proteins (RBPs) are emerging as important players in regulating eukaryotic gene expression and genome stability. Specific RBPs have been shown to mediate various chromatin-associated processes ranging from transcription to gene silencing and DNA repair. One of the prominent classes of RBPs is the KH domain-containing proteins. Vigilin, an evolutionarily conserved KH domain-containing RBP has been shown to be associated with diverse biological processes like RNA transport and metabolism, sterol metabolism, chromosome segregation, and carcinogenesis. We have previously reported that vigilin is essential for heterochromatin-mediated gene silencing in fission yeast. More recently, we have identified that vigilin in humans plays a critical role in efficient repair of DNA double-stranded breaks and functions in homology-directed DNA repair. In this review, we highlight the multifaceted functions of vigilin and discuss the findings in the context of gene expression, genome organization, cancer, and autism-related disorders.
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Affiliation(s)
- Arjamand Mushtaq
- Centre for Interdisciplinary Research and Innovations, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Ulfat Syed Mir
- Centre for Interdisciplinary Research and Innovations, University of Kashmir, Srinagar, Jammu and Kashmir, India
| | - Mohammad Altaf
- Centre for Interdisciplinary Research and Innovations, University of Kashmir, Srinagar, Jammu and Kashmir, India.
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47
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Sarker AH, Cooper PK. Slot Blot Assay for Detection of R Loops. Methods Mol Biol 2023; 2701:149-156. [PMID: 37574480 DOI: 10.1007/978-1-0716-3373-1_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
R loops (DNA-RNA hybrid) are three-stranded nucleic acid structures that comprise of template DNA strand hybridized with the nascent RNA leaving the displaced non-template strand. Although a programmed R loop formation can serve as powerful regulators of gene expression, these structures can also turn into major sources of genomic instability and contribute to the development of diseases. Therefore, understanding how cells prevent the deleterious consequences of R loops yet allow R loop formation to participate in various physiological processes will help to understand how their homeostasis is maintained. Detection and quantitative measurements of R loops are critical that largely relied on S9.6 antibody. Immunofluorescence methods are frequently used to localize and quantify R loops in the cell but they require specialized tools for analysis and relatively expensive; therefore, they are not always useful for initial assessments of R loop accumulation. Here, we describe an improved slot blot protocol to detect and estimate R loops and show its sensitivity and specificity using the S9.6 antibody. Since specific factors protecting cells from harmful R loop accumulation are expanding, this protocol can be used to determine R loop accumulation in research and clinical settings.
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Affiliation(s)
- Altaf H Sarker
- Department of BioEngineering and BioMedical Sciences, Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Priscilla K Cooper
- Department of BioEngineering and BioMedical Sciences, Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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48
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RAD18 opposes transcription-associated genome instability through FANCD2 recruitment. PLoS Genet 2022; 18:e1010309. [DOI: 10.1371/journal.pgen.1010309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 12/20/2022] [Accepted: 11/22/2022] [Indexed: 12/13/2022] Open
Abstract
DNA replication is a vulnerable time for genome stability maintenance. Intrinsic stressors, as well as oncogenic stress, can challenge replication by fostering conflicts with transcription and stabilizing DNA:RNA hybrids. RAD18 is an E3 ubiquitin ligase for PCNA that is involved in coordinating DNA damage tolerance pathways to preserve genome stability during replication. In this study, we show that RAD18 deficient cells have higher levels of transcription-replication conflicts and accumulate DNA:RNA hybrids that induce DNA double strand breaks and replication stress. We find that these effects are driven in part by failure to recruit the Fanconi Anemia protein FANCD2 at difficult to replicate and R-loop prone genomic sites. FANCD2 activation caused by splicing inhibition or aphidicolin treatment is critically dependent on RAD18 activity. Thus, we highlight a RAD18-dependent pathway promoting FANCD2-mediated suppression of R-loops and transcription-replication conflicts.
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49
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Hodson C, van Twest S, Dylewska M, O'Rourke JJ, Tan W, Murphy VJ, Walia M, Abbouche L, Nieminuszczy J, Dunn E, Bythell-Douglas R, Heierhorst J, Niedzwiedz W, Deans AJ. Branchpoint translocation by fork remodelers as a general mechanism of R-loop removal. Cell Rep 2022; 41:111749. [PMID: 36476850 DOI: 10.1016/j.celrep.2022.111749] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 10/05/2022] [Accepted: 11/09/2022] [Indexed: 12/12/2022] Open
Abstract
Co-transcriptional R loops arise from stalling of RNA polymerase, leading to the formation of stable DNA:RNA hybrids. Unresolved R loops promote genome instability but are counteracted by helicases and nucleases. Here, we show that branchpoint translocases are a third class of R-loop-displacing enzyme in vitro. In cells, deficiency in the Fanconi-anemia-associated branchpoint translocase FANCM causes R-loop accumulation, particularly after treatment with DNA:RNA-hybrid-stabilizing agents. This correlates with FANCM localization at R-loop-prone regions of the genome. Moreover, other branchpoint translocases associated with human disease, such as SMARCAL1 and ZRANB3, and those from lower organisms can also remove R loops in vitro. Branchpoint translocases are more potent than helicases in resolving R loops, indicating their evolutionary important role in R-loop suppression. In human cells, FANCM, SMARCAL1, and ZRANB3 depletion causes additive effects on R-loop accumulation and DNA damage. Our work reveals a mechanistic basis for R-loop displacement that is linked to genome stability.
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Affiliation(s)
- Charlotte Hodson
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Sylvie van Twest
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | | | - Julienne J O'Rourke
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Winnie Tan
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Vincent J Murphy
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Mannu Walia
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Lara Abbouche
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | | | - Elyse Dunn
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Rohan Bythell-Douglas
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | - Jörg Heierhorst
- Department of Medicine (St Vincent's Health), University of Melbourne, Fitzroy, VIC 3065, Australia; Molecular Genetics Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia
| | | | - Andrew J Deans
- Genome Stability Unit, St. Vincent's Institute of Medical Research, Fitzroy, VIC 3065, Australia; Department of Medicine (St Vincent's Health), University of Melbourne, Fitzroy, VIC 3065, Australia.
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50
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Koyanagi E, Kakimoto Y, Minamisawa T, Yoshifuji F, Natsume T, Higashitani A, Ogi T, Carr AM, Kanemaki MT, Daigaku Y. Global landscape of replicative DNA polymerase usage in the human genome. Nat Commun 2022; 13:7221. [PMID: 36434012 PMCID: PMC9700718 DOI: 10.1038/s41467-022-34929-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 11/11/2022] [Indexed: 11/27/2022] Open
Abstract
The division of labour among DNA polymerase underlies the accuracy and efficiency of replication. However, the roles of replicative polymerases have not been directly established in human cells. We developed polymerase usage sequencing (Pu-seq) in HCT116 cells and mapped Polε and Polα usage genome wide. The polymerase usage profiles show Polε synthesises the leading strand and Polα contributes mainly to lagging strand synthesis. Combining the Polε and Polα profiles, we accurately predict the genome-wide pattern of fork directionality plus zones of replication initiation and termination. We confirm that transcriptional activity contributes to the pattern of initiation and termination and, by separately analysing the effect of transcription on co-directional and converging forks, demonstrate that coupled DNA synthesis of leading and lagging strands is compromised by transcription in both co-directional and convergent forks. Polymerase uncoupling is particularly evident in the vicinity of large genes, including the two most unstable common fragile sites, FRA3B and FRA3D, thus linking transcription-induced polymerase uncoupling to chromosomal instability. Together, our result demonstrated that Pu-seq in human cells provides a powerful and straightforward methodology to explore DNA polymerase usage and replication fork dynamics.
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Affiliation(s)
- Eri Koyanagi
- grid.69566.3a0000 0001 2248 6943Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
| | - Yoko Kakimoto
- grid.69566.3a0000 0001 2248 6943Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
| | - Tamiko Minamisawa
- grid.410807.a0000 0001 0037 4131Cancer Genome Dynamics project, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Fumiya Yoshifuji
- grid.69566.3a0000 0001 2248 6943Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Toyoaki Natsume
- grid.418987.b0000 0004 1764 2181National Institute of Genetics, Research Organization of Information and Systems (ROIS), Mishima, Japan ,grid.275033.00000 0004 1763 208XDepartment of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Mishima, Japan ,grid.272456.00000 0000 9343 3630Present Address: Research Center for Genome & Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Atsushi Higashitani
- grid.69566.3a0000 0001 2248 6943Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Tomoo Ogi
- grid.27476.300000 0001 0943 978XResearch Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Antony M. Carr
- grid.12082.390000 0004 1936 7590Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Falmer, BN1 9RQ UK
| | - Masato T. Kanemaki
- grid.418987.b0000 0004 1764 2181National Institute of Genetics, Research Organization of Information and Systems (ROIS), Mishima, Japan ,grid.275033.00000 0004 1763 208XDepartment of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Mishima, Japan ,grid.26999.3d0000 0001 2151 536XDepartment of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Yasukazu Daigaku
- grid.69566.3a0000 0001 2248 6943Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan ,grid.410807.a0000 0001 0037 4131Cancer Genome Dynamics project, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan
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